Bug fix: Fix endless loop when ATR is not received

Without this fix, if the host software does not send an ATR, simtrace
waits for this answer in an endless loop of unsuccessfull USB
endpoint write attempts.
diff --git a/sam3s_example/simtrace/phone.c b/sam3s_example/simtrace/phone.c
index 8c84be7..ec50d68 100644
--- a/sam3s_example/simtrace/phone.c
+++ b/sam3s_example/simtrace/phone.c
@@ -152,7 +152,7 @@
 */
     // FIXME: What to do on reset?
     // FIXME: It seems like the phone is constantly sending a lot of these RSTs
-//    PIO_DisableIt( &pinPhoneRST ) ;
+    PIO_DisableIt( &pinPhoneRST ) ;
 }
 
 static void Config_PhoneRST_IrqHandler()
@@ -301,6 +301,7 @@
         _ISO7816_SendChar(*(ATR++));
     }
     state = WAIT_CMD_PHONE;
+    PIO_EnableIt( &pinPhoneRST ) ;
 }
 
 void sendResponse( uint8_t *pArg, uint8_t status, uint32_t transferred, uint32_t remaining)